council tax number starting with 22?!

I have a council tax reference number from a letter I received
That number is 8 digits long and starts with the number 4

I go to the website to pay my council tax and it says the number should be 10 digits long and start with 22



I have a letter from where they tried to summoned me last time when I was struggling to find out how to pay.. and they charged me an extra £100.. And that letter doesn't have a 10 digit number on it..

I want to find out how much I owe too . I have no idea... until they send me a summons again.

I dont' always remember how much I paid.. I need to find out how much I owe based on how much i've paid..